Neurovascular decompression for hemifacial spasm.

Results of 23 cases of facial spasm operated on by posterior fossa exploration were reviewed. In all cases, but one, vessels were found to impinge on the facial nerve root exit zone from the brain stem. All cases in which the facial nerve had been liberated from the vessel had satisfactory results and there was no recurrence of spasm. Significant sensorineural hearing loss occurred postoperatively in 11 cases. The hearing loss greatly improved within a month and persisted as permanent loss greater than 10 dB in 6 cases (26.0%). The complication has been lessened by approaching to the nerve from caudal direction and by retracting the cerebellum to oblique direction to the acoustic nerve. Microvascular decompression is the best procedure available for hemifacial spasm.